| Part 1 The added value of regional hybrid PET/MR fusion imaging in the diagnosis for primary hepatic carcinoma:comparison with 18F-FDG PET/CTPurpose:The aim of this study was to explore the added value of regional hybrid PET/MR fusion imaging in patients with primary hepatic carcinoma(PHC)compared with 18F-FDG PET/CT.Procedures:Thirty-one patients with clinical suspected PHC underwent 18F-FDG PET/CT and MR examinations,which were conducted within two weeks of each other.Hybrid PET/MR fusion images were achieved by fusing PET and MR images in the GE Discovery STE16 workstation AW4.6.Blind imaging interpretations of these three different modal images were performed and compared with clinical and pathological diagnosis.All patients were divided into two groups according to the lesion size:one is small PHC group(?3cm)and the other one is large PHC group(>3cm).The diagnostic value of hybrid 18F-FDG PET/MR for PHC was compared with 18F-FDG PET/CT.Results:Eighteen patients were in the large PHC group and the other 13 patients were in small PHC group.In the large PHC group,16 patients were diagnosed with PHC,one was diagnosed with liver metastasis and one was with hemangioma.The sensitivity,positive predictive value(PPV)and accuracy of MR for diagnosing large PHC were 100%,94.1%and 94.4%,respectively,which were same to that of PET/CT.On the other hand,the sensitivity,PPV and accuracy of hybrid PET/MR for diagnosing large PHC were all 100%.However,no statistical difference was observed between PET/MR and PET/CT regarding the diagnostic efficacy for large PHC(Kappa=0.64).In small PHC group,9 patients were diagnosed with PHC and 4 were diagnosed with benign liver disease.The sensitivity,PPV and negative predictive value(NPV)and accuracy of PET/CT for small PHC were 55%,83.3%,42.9%and 61.5%,respectively.Meanwhile,the sensitivity,PPV,NPV and accuracy of PET/MR for diagnosis of small PHC were 100%,90%,100%and 92.3%,respectively,which were same to MR.PET/MR demonstrated significantly higher diagnostic efficacy for PHC than that of PET/CT.PET/MR and PET/CT were less consistent in the diagnosis of small PHC(Kappa=0.11).Conclusions:Compared with 18FDG PET/CT,hybrid PET/MR fusion imaging didn't provide additional information in the sensitivity of large PHC diagnosis,but was able to reduce the false positive rate in a certain extent.However,regarding the diagnosis of small PHC,hybrid PET/MR was more sensitive than PET/CT and therefore,could be used as a complementary imaging technology in the situation in which PET/CT findings are not diagnostic.Part 2 The added value of regional hybrid PET/MR fusion imaging in the postoperative follow-up for primary hepatic carcinoma:comparison with 18F-FDG PET/CTPurpose:The aim of this study was to explore the added value of regional hybrid PET/MR fusion imaging in the postoperative follow-up for primary hepatic carcinoma(PHC)compared with 18F-FDG PET/CT and MR.Procedures:Twenty-one postoperative patients with PHC underwent 18F-FDG PET/CT and MR examinations,which were conducted within two weeks of each other.Hybrid PET/MR fusion images were achieved by fusing PET and MR images in the GE Discovery STE16 workstation AW4.6.Blind imaging interpretations of these three different modal images were performed and compared with clinical follow-up.The overall curative effect was evaluated and compared by hybrid PET/MR,PET/CT or MR in all patients.In addition,the detection rates of PET/MR,PET/CT and MR for recurrence or metastasis(ROM)were compared in three different regions,which included operative region,intrahepatic region out of operation(IROP)and extrahepatic region within fusion area(ERWF).Results:Data on these 21 patients were used in the follow-up analysis,13 patients were confirmed of ROM(61.9%),while the other 8 patients were confirmed of having no ROM.Of the 13 patients with ROM,7 were detected by MR and 9 were detected by hybrid PET/MR,the detection rate of MR and PET/MR was 53.8%and 69.2%,respectively.However,all 13 ROM patients were detected by whole-body PET/CT,and its detection rate was 100%.Regarding to the ROM patients,6 patients were confirmed to have locoregional recurrence within the operative region.Of the 6 lesions,only one was detected by MR(16.7%)but all 6 lesions were detected by either hybrid PET/MR or PET/CT(100%).Therefore,both PET/MR and PET/CT demonstrated significantly higher sensitivity than MR for evaluating the locoregional recurrence within the operative region.On the other hand,4 lesions were confirmed in IROP,including 1 with portal vein tumor thrombus,and the 4 lesions were all clearly demonstrated by PET/MR,MR and PET/CT(100%).As such,there were no significant difference between different imaging modalities for evaluating metastases in IROP(p>0.05).Regarding the ERWF,3 lymph nodes and 1 peritoneal metastases were all detected by PET/MR,MR and PET/CT.Likewise,all three imaging modalities demonstrated similar sensitivity for evaluating metastases in ERWF(p>0.05).Furthermore,whole-body PET/CT imaging found 3 additional distant metastases in the region outside the fusion area.Conclusions:The postoperative evaluation of hybrid PET/MR and PET/CT fusion imaging was consistent in PHC,which demonstrated significantly higher detection rate than MR for evaluating the locoregional recurrence within the operative region.However,all three imaging modalities demonstrated similar sensitivity for evaluating metastases in IROP and ERWF.Compared with MR,hybrid PET/MR imaging could obviously optimize the visual effect in metastatic lesions such as lymph nodes,peritoneal metastasis and portal vein tumor thrombus,which could improve the diagnostic confidence. |
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